1. Technical Field
The present invention relates to a light guiding device or the like guiding video light to present a video formed by an image display element or the like to an observer, and more particularly, to a transmissive display apparatus such as a virtual image display apparatus suitable for a head-mounted display mounted on the head of an observer.
2. Related Art
Various optical systems embedded in transmissive display apparatuses such as head-mounted displays (hereinafter also referred to as HMDs) mounted on heads of observers have been proposed (for example, see JP-A-2012-163662, JP-A-6-51264, and JP-A-2009-128649). For example, there is a known method of depolarizing guided video light by disposing a depolarization element on an optical path of the video light (see JP-A-2012-163662).
In transmissive display apparatuses configuring see-through optical systems superimposing such video light and outside light, light use efficiency can be improved, for example, when portions (combiner portions) superimposing the video light and the outside light are configured by films such as half mirrors with different transmission and a reflection property of P/S polarization (see JP-A-6-51264 and JP-A-2009-128649). However, there is a possibility of the outside light seen over the films such as the half mirrors being darkened or colored. In particular, when the outside light has a polarization property like image light from a liquid crystal panel or the like, the outside light is considered to be considerably darkened or colored.